Fixed Typo in README

Author: rootsec1

README.md

@@ -215,7 +215,7 @@ FractionallySizedBox is build exactly for that usecase. Just give it the fractio
 
 ## #Day15 Flexible vs Expanded
 
-Expandable() is nothing more than Flexible() with 
+Expanded() is nothing more than Flexible() with 
 
     Flexible (fit: FlexFit.tight) = Expanded()
 
@@ -545,4 +545,4 @@ The following animation is done with just `AnimatedContainer()`
 
 [play with the animation in codepen](https://codepen.io/erluxman/pen/MWaEZEz)
 
-![](assets/28animatedcontainer.gif)
+![](assets/28animatedcontainer.gif)